Cooling system for internal combustion engines



Patented Feb. 15,1944

COOLING SYSTEM FOR INTERNAL COLIBUSTION ENGINES James E. Justus, Beloit, Wis., assignor to Fairbanks, Morse & 00., Chicago, 111., a corporation of Illinois Application June 10, 1942, Serial No. 446,483

3 Claims.

' This invention relates to cooling systems for internal combustion engines and particularly to improved means for controlling engine temperature.

The principal object of theinvention resides in the provision of improved means for controlling and maintaining within a limited range the temperature of internal combustion engines employed for vehicle propulsion, especially railwaylocomotives, under varying conditions ofiloading, speed and ambient air temperature. More particularly an object of the invention is attained in the provision of improved means for controlling the rate of air flow through the radiator of a fluid cooled engine, in accordance with the temperature of the cooling fluid, and involves the joint control of an air impeller and a system of adjustable vanes or louvers associated with the engine radiator.

Other objects and advantages will appear from the following description and accompanying drawing setting forth the invention.

In the drawing, Fig. 1 is a diagrammatic side elevational view of a railway locomotive powered by an oil or gas engine utilizing the coolingair temperature control system of my invention;

Fig. 2 illustrates, diagrammatically, the means employed for controlling the flow of air through the radiator, and

Fig. 3 is a wiring diagram for the motor that drives the air impeller.

Referring now by characters of reference to the drawing, Fig. 1 illustrates a railway locomotive in which has for its prime source of power a Diesel engine H. The engine H is provided with conventional cooling equipment, including cylinder water jackets and a heat exchanger or radiator l2 suitably connected to the jacket by forward and return pipes l3 and M. In the present installation the radiator I2 is mounted horizontally, subjacent an opening in the roof of the locomotive cab, at the discharge end of a conduit that takes in air through openings in the opposite sides of the cab near the floor level. These intake openings are provided with shutter or damper devices, each comprising an assemblage of vertically disposed, adjustable louvers or vanes indicated generallyat l5, arranged to be opened coordinately and to varying degrees between fullopen and -closedpositions.

The louvers l5 are adapted to pick up air from the slip stream and as will be understood, the volume of air inducted for passage through the radiator is proportional to the degree to which the louvers I5 are opened. The flow of air through the radiator is adapted to be augmented by an impeller l6 suitably mounted within the conduit between the louvers l5 and radiator l2, such impeller being driven by an electric motor I! of variable speed type.

The operation of the louvers l5 and control of' fan speed is effected through the operation of a hydraulic servo-motor under the control of a temperature responsive device influenced by the temperature of the jacket water. Such a temperature nected by a rod 2| to a lever 22 which in'turn is connected by a laterally extending tie bar to the upper end of a lever 24. Lever 24 is fulcrumed at its lower end on the piston rod 25 of the servomotor, designated generally at 26, and isconnected at an intermediate point to the valve control rod 2! of the servo-motor. Rod 21 extends into a valve chest 28 and by means of a pair of spaced, piston-like valve members 29, 29' controls the flow of fluid under pressure to the cylinder space on the opposite sides of the double acting piston 30. A connection with the pressure side of the lubricating oil system is made by pipe 3| which communicates with the interior of the valve chest 28 at a point between the valves 29, and thence with the cylinder at opposite sides of the piston through passages 32 and 32. Pipes 33 and 33' connect the ends of the valve chest 28 to the low pressure or return side of the oil circulating system. The piston rod 25 of the servomotor is operatively connected by suitable linkage, including a lever 34, to the louvers 15.

The operation and speed of fan I6 is coordinated with the operation of louvers I5 in the following manner. The fan motor H, in the present example of two speed type, is under the control of two switches, a low speed switch 35 and a high speed switch 3-6. These switches have speed switch 30 is accordingly restored and actuating plungers 35a and 36a adapted to be depressed sequentially by a rod member 31 mounted for endwise movement in a guide sleeve 88 carried by a bracket 89. As will be understood from the drawing, depression of the actuating plungers to open their associated switches is accomplished through a camming action of the rod 31 as it moves toward the right across the ends of the plungers. The rod 31 is connected to the piston rod 26 so as to move therewith, there being provided an arm member 46 secured to the piston rod 26 and having a lostmotion connection ll with rod 31. Such lost motion connection desirably prevents the switches from responding to insignificant movements of rod 25. Fig. 3 illustrates the electrical circuit connection for the fan motor H. In this figure the power supply lines are designated 62. The low 35 connects the motor I! to the supply lines through a suitable resistance unit 43, and the high speed switch, when closed, connects the motor directly to the supply lines.

The manner in which the described mechanism operates to control engine temperature is as follows. First, it will be understood that during those periods wherein the temperature of the Jacket water at the bulb 20 is constant, that is, neither rising nor failing, the positions of valves 26 and 29' are as shown in Fig. 2, the ports for both passages 32 and 32' being open and in communication with the high pressure line 3!. Under these conditions equal pressure is exerted on the opposite sides oi piston 80 and consequently it remains stationary. Now, if the temperature of the Jacket water in pipe 13 rises, the bellows l8 will" expand and move the levers 22 and 24, and thereby the valve piston, to the right. The valve 29 is thus caused to move across the port 32 relieving the pressure from that passage by placing it in communication with the low pressure or return line 33. During this transition period passage 32' continues to be in communication with the high pressure line 3|. The now unbalanced pressures on the opposite sides of the main piston 36 causes that member to shift toward the left, and in so doing moves the valve piston back to its former, normal position wherein both of the passages 32 and 32' communicate with the high pressure lin 3|. Equal pressure on the opposite sides of the main piston the main piston comes to rest in a new position to the left of its former position, its movement in such direction having opened the louvers l to a greater extent.

The control of tan speed through switches 35 1 and 36 is coordinated with the louver control above described. With the louvers in full open position the switch operating rod 31 is disengaged from the plunger 36a of the high speed switch 36 which, under this circumstance, is closed (Fig. 3). The fan motor then operates at high speed under full line voltage. As the temperature of the jacket water drops, switch rod 31 moves to the right and opens switch 36 so that the fan motor is energized at reduced voltage, and hence reduced speed, through switch 35' and resistance unit 43. With continued lowering of the engine jacket temperature rod 31 moves into en agement with and depresses plunger 35a to open the low speed switch 35, and since switch 36 is also being held open by red 31 the fan motor becomes completely deenergized and ceases to operate. The operation of the fan as coordinated with that of the louvers in a temperature control system oi the described character, where engine Jacket temperatures are desired to be maintained at about 160 degrees F. will be understood from the following table of exemplary figures.

Increased temperatures 7 Degrees Louvers closed Louvers 50% open.

running Decreased temperatures Degrees Louvers 100% open, and high speed fan running 165 Louvers 90% open, and high speed tan stopped, and low speed runningl 164 Louvers 55% open, and low speed tan stopped 160% Louver closed 155 -Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In combination in an engine cooling system including a radiator, a variable speed, motordriven fan and a shutter device for varying the flow of air through said radiator, con rrol means for said fan and shutter device, said mean including a shaft arranged for endwise movement to open and close said shutter device, a plurality of fan speed control switches and an operating member common to said switches, said member being connected for movement with said shaft and adapted to close said switches sequentially to increase the fan speed when said shaft is moved in one direction.

2. In combination in an engine cooling system including a radiator, a variable speed motordriven fan and a shutter device for varying the flow of air through said radiator, control means for said fan and shutter device, comprising a plurality of fan speed control switches having individual, aligned actuating fingers, a member movable along the line of said switch fingers adapted sequentially to engage and operate the same, an operating member for said shutter device, and means connecting said switch operating member for movement by said shutter operating member, said means including a lost-motion device for permitting limited movement of said shutter operating member independently of said switch operating member.

3. In combination in an engine cooling system including a radiator, means for varying the flow of air through said radiator, comprising a shutter device and a variable speed motor-driven tan, power means of cylinder and piston type connected to said shutter device to open and close the same, a thermal-responsive device subject to engine temperature for controlling said power means, a plurality of fan speed control switches having actuating fingers disposed in alignment, an operating member movable along the line of said switches and adapted by cams to engage and operate said fingers sequentially to effect staged variations of fan speed, and means connecting said switch operating member for movement by the piston of said power means, including a lostmotion device for permitting limited movement of said piston independently of said switch operating member.

JAMES E. JUSTUS. 

